Noonan Syndrome and Systemic Lupus Erythematosus: Association or Risk Factor?

Abstract

Aim: The RAS/MAPK signaling pathway proteins with germline mutations in their respective genes are associated with several disorders such as Noonan, LEOPARD, neurofibromatosis type 1, Costello and cardio-facio-cutaneous syndromes. Some monogenic conditions are associated with the development of systemic lupus erythematosus (SLE), in medical literature are few reports that describe the association of RAS opathies and autoimmune disease. Our aim was to describe the clinical picture of a patient with diagnosis of Noonan and SLE. Methods: We report a clinical case of a 24-year-old woman with Noonan syndrome who developed SLE according to American College of Rheumatology criteria for the classification of SLE. The patient had arthritis, serositis, lymphopenia, proteinuria, high levels of antinuclear antibodies and anti-ds DNA positive. This rare association then driven to search the medical literature for English articles on the subjects of Noonan and SLE in Pubmed. Results: Our patient had oligoarthritis, serositis, lymphopenia, ISN/RPS Class IV lupus nephritis, ANA 1:1280 homogeneous pattern and anti-dsDNA antibodies very similar to the 8 patients already reported in literature. Conclusion: There are nine cases reported with the association of two rare diseases, Noonan syndrome and SLE, this connection could suggests that RAS opathies may be a risk factor to the development of autoimmune disorders.